Basic Information Sheet: African Pygmy Hedgehog

African Pygmy Hedgehog (Atelerix albiventris)

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Natural history


The African pygmy hedgehog is a native of West and Central Africa.

The African pygmy hedgehog (Atelerix albiventris), also known as the central African, white-bellied, or four-toed hedgehog (Banks 2010), is native to the savannah and steppe regions of Central Africa, extending from Somalia in the East and Senegal in the West (Cassola 2016, Banks 2010, Reeve 1994).

The pet African pygmy hedgehog is probably descended from hybrids of the North African or Algerian hedgehog (A. algirus) and the African hedgehog (Graesser et al. 2006). All pet hedgehogs in the United State are captive-bred.

In 1991, it became illegal to import hedgehogs from Africa into the United States because African hedgehogs can carry foot and mouth disease (Ivey & Carpenter 2012, Riley & Chomel 2015). The potential transmission of foot and mouth disease to cattle (Ivey & Carpenter 2012, Riley & Chomel 2015) has also made hedgehogs illegal in some states and municipalities. A permit is required in some states and a permit from the United States Department of Agriculture is required for persons who breed, transport, sell, exhibit or use HH for research or teaching purposes. (Ivey & Carpenter 2012)

Taxonomy



Class: Mammalia

Order: Insectivora (Eulipotyphla) (Cassola 2016)

Family: Erinaceidae

Conservation status


The International Union for Conservation of Nature Red List lists Atelerix albiventris as a species of least concern. The population is stable (Cassola 2016).

Diet


Hedgehogs are omnivores however they mainly consume a variety of invertebrates. Hedgehogs also feed on, frogs, lizards, snakes, small mammals,, carrion, as well as vegetables, and fruit in the wild (Dierenfeld 2009).

Captive diets typically consist of a moderate level of protein (30%-50%, dry basis) and fat (10%-20%) (Dierenfeld 2009).:

  1. Protein sources such as high-quality, reduced-calorie cat food (2-3 tsp), live insects (5-6 mealworms or 1-2 crickets 3-4 times weekly), avoid waxworms; bird of prey diet, insectivore diet , or hedgehog diet.
  2. Produce such as chopped mixed vegetables and/or fruits (1-2 tsp)
  3. Avoid dairy products and eggs in non-breeding pets.

Fresh water should be available at all times.

Husbandry

Cage designHouse “hedgies” in an enclosure with smooth walls and flooring such as 15-20 gallon aquarium with a secure, wire mesh lid.

Hedgehogs are nocturnal and they prefer a quiet, dim environment.

SubstrateProvide about 10 cm of soft, absorbent bedding (recycled paper product, aspen shavings) to allow burrowing.
Cage furnitureProvide visual security in the form of a cardboard box with one open end, a plastic flower pot, hollow tubes, such as PVC piping, plants, or logs. If multiple hedgehogs are housed together, provide one hide box per animal (Ivey & Carpenter 2012).

Some hedgehogs may also be litter box trained (Ivey & Carpenter 2012). Alfalfa pellets or recycled paper product generally work best.

Solid exercise wheels provide exercise and enrichment opportunities (Banks 2010, Ivey & Carpenter 2012)
Other enrichment items can include swimming tubs, climbing structures, straw or hay, and cardboard tubes (Banks 2010, Ivey & Carpenter 2012)

Target environmental humidityLow humidity < 40% is preferred (Banks 2010) (Ivey & Carpenter 2012)
Target environmental temperature (Ivey & Carpenter 2012)75-85°F24-30°C
In a hospital setting, maintain weak or debilitated hedgehogs between 80-85°F (27-29°C). (Ivey & Carpenter)

To prevent torpor, provide supplemental heating if temperature falls below 65°F (18°C). Below this temperature, hedgehogs becomes inactive and the immune system is compromised. (Heatley, 2009)

Normal physiologic values

Body temperature (see Metabolism below)(Ivey & Carpenter)95.7-98.6°F35.4-37.0°C
Pulse180-280 bpm
Respiration25-50 bpm
Body weightAdult male400-600 g (Ivey & Carpenter)
Adult female250-400 g (Banks 2010)
Mean life span3-5 years4-6 years (Ivey & Carpenter)
Up to 10y recorded
Sexual maturityMale 2-6 months (Heatley 2009)
Female 6-8 months (Heatley 2009)
Females sexually mature at 2 months but should not be bred before 6 months of age (Banks 2010)
First breeding at 6-8 months
Gestation (Bedford) (Ivey & Carpenter 2012)34-37 days (Banks 2010)
Litter size (Bedford)1-9 pups (Ivey & Carpenter)(average 3-4) (Ivey & Carpenter, Banks 2010)
Birth weight10-18 g (Ivey & Carpenter)
Eyes open13-2414-18 days (Ivey & Carpenter)
Weaning age (Bedford)4-6 weeksBegin eating solids at 3 weeks (Ivey & Carpenter)

Anatomy ⁄Physiology

DermatologyThe legs and ventral surface of the hedgehog are covered with light-colored fur.

The mantle is the dorsum of the hedgehog, which is covered with thousands of smooth, hollow spines made of keratin (Ivey & Carpenter 2012, Terlutter 1984).

  • The spines serve to protect hedgehogs from predators, they buffer falls and help the thermoregulation (in winter) (Schicht-Tinbergen 1995). Beneath the spines sits a large, fat-filled subcutaneous layer and a powerful muscle layer (orbicularis muscle) (Ivey & Carpenter 2012).

Juvenile hedgehogs are born with “nest spines” that sit just beneath the skin and emerge within hours after birth (Banks 2010). “Nest spines” are shed at 1 month of age and are replaced with permanent spines, which last up to 18 months and are replaced one at a time (Ivey & Carpenter 2012).

Dental formulaI (3/2) C (1/1) PM (3/2) M (3/3) = 36 teeth (Ivey & Carpenter 2012, Banks 2010)

  • Hedgehog teeth are more blunt than in most insectivores.
  • The incisors are sharp, canines are small, and the molars and premolars are flat and broad (Banks 2010)

Deciduous teeth erupt between 18-23 days permanent teeth erupt 7-9 weeks (Banks 2010)

Gastrointestinal tractHedgehogs possess a simple stomach and lack a cecum. Gastrointestinal transit time is 12-16 hours (Ivey Carpenter 2012)
MusculoskeletalWhen threatened, the hedgehog curls into a ball by contracting the panniculus muscle. (It also extends its spines, puffs up, and hisses). Hedgehogs can remain rolled up for hours with relatively little muscular effort (Ivey & Carpenter 2012).

Most hedgehogs have five toes, but the African pygmy hedgehog only has four toes on the rear foot.(Banks 2010)

The tibia and fibula are fused distally (Ivey & Carpenter 2012). The radius and ulna are also fused. (Banks 2010, Heatley 2008)

ReproductionThe penis is external and located on the mid-ventral abdomen (Banks 2010). The testicles are often abdominal, and are not easily palpable. (D’Agostino). Pressure on the abdomen can push the testicles into the inguinal space.

Hedgehogs are polygamous.

Female hedgehogs possess a bicornuate uterus and a single cervix. (Banks 2010)

  • Spontaneous ovulators (Ivey & Carpenter 2012)
  • Capable of breeding at a young age (2 months) (Banks 2010)

Polyestrous, breed throughout the year in captivity (Ivey & Carpenter 2012)

Milk composition (Ivey & Carpenter)
Protein 16g/100g
Fat 25.5g/100g
CHO trace

See additional information in physiologic values above.

Special sensesHedgehogs have a keen sense of smell and hearing and poor eyesight (Banks 2010, Ivey & Carpenter 2012, D’Agostino).
MetabolismLike most insectivores, hedgehog body temperature is relatively low

All hedgehogs are capable of entering torpor during periods of cool, dry weather (temp <65°F or 18°C) for up to 6 weeks (Ivey & Carpenter 2012). Body temperature can drop as low as 1°C (D’Agostino). Excessively high environmental temperatures can also induce a torpid state. (Ivey & Carpenter)

Physical activity


Hedgehogs are adept at climbing, digging, swimming and jogging (Ivey & Carpenter 2012).
Normal HH gait is slow and steady waddle but they are capable of bursts of speed (Ivey & Carpenter 2012).

HH can be placed into a large escape-proof enclosure for exercise on a daily basis (Banks 2010, Ivey & Carpenter 2012). Solid exercise wheels provide exercise and enrichment opportunities (Banks 2010, Ivey & Carpenter 2012). Other enrichment items can include swimming tubs, climbing structures, straw or hay, and cardboard tubes (Banks 2010, Ivey & Carpenter 2012)


Behavior

NocturnalHedgehogs are nocturnal and they prefer a quiet, dim environment.
Social structureHedgehogs are solitary creatures that are generally housed alone. Males are particularly likely to fight. (Smith 1992).

If multiple hedgehogs are housed together, provide one hide box per animal (Ivey & Carpenter 2012).

Defensive behaviorWhen threatened, the hedgehog curls into a ball by contracting the panniculus muscle, to protect the vulnerable ventrum and feet (Banks 2010). Hedgehogs can remain rolled up for hours with relatively little muscular effort (Ivey & Carpenter 2012).

The hedgehog’s spines, which extend along its head and back, are also a deterrent to predators. Threatened hedgehogs will hiss, puff up, and extend the spines (found along the dorsum).

Self anointingWhen exposed to a new object, hedgehogs may exhibit a unique “self anointing” or “anting” behavior where they place their thick, frothy saliva onto their spines (D’Agostino, Burton 1958). Encounter a new or irritating substance > lick substance until saliva is produced > then vigorously groom its quills. The reason for this behavior is unknown. (D’Agostino)

Restraint

  • African hedgehogs rarely bite but adult males may hiss (Banks 2010).
  • Even the tamest hedgehog tends to roll into a ball when touched (Banks 2010, D’Agostino), therefore a careful visual exam should always proceed hands-on care.
  • Inspection of the stomach may be impossible (Fehr and Sassenburg 2015).
  • Hedgehogs are tame for their owners if handled consistently from an early age (D’Agostino, Ivey & Carpenter), however light leather gloves are required to handle all but the tamest hedgehogs (D’Agostino, Ivey & Carpenter 2012).
  • Gently extend the ear legs to “wheel-barrow” the hedgehog and place a finger underneath the chin to prevent the hedgehog from rolling up (Ivey & Carpenter 2012) If rolled up, a gently stroke of the back spines may trigger a relaxation and the hedgehog stretches out (Fehr and Sassenburg 2015).
  • Use sedation or general anesthesia for complete examination or procedures.


Diagnostics


Venipuncture

Use the jugular vein for larger volumes, and use the cephalic, lateral saphenous, or femoral veins for small volumes. (Campbell and Ellis 2007; Campbell 2012; Rossi et al. 2013)

Radiography

Spines greatly reduce radiographic detail. Plastic clips or tape can be used to gently pull dorsal skin away from the chest and abdomen to improve detail. (D’Agostino)

Anesthesia is required for proper positioning (Ivey & Carpenter, D’Agostino).

Preventive medicine


  • Biannual or annual physical examination (Ivey & Carpenter)
  • Routinely monitor body weight and body condition
    An African hedgehog with a normal body condition score should be able to roll up completely without any evidence of protruding fat deposits. (Ivey & Carpenter 2012). Overweight hedgehogs typically develop large axillary fat depots (Ivey & Carpenter).
  • Regular dental cleanings (tartar control cat treats can be helpful
  • Routine toe nail trims (often anesthesia is necessary)
  • Microchip implantation for collections
  • Surgical sterilization is generally not necessary since most hedgehogs are housed alone

Therapeutics



Hospitalization

Maintain weak or debilitated hedgehogs between 80-85°F (27-29°C). (Ivey & Carpenter)
Provide familiar food items whenever possible. Live invertebrates may also stimulate feeding.

In hospital: for weak or debilitated HH

Oral

Oral medications can be difficult to impossible to administer to hedgehogs. Some patients will accept fruit-flavored medications via syringe (Ivey & Carpenter). Mealworms injected with medication can also be offer per os (Banks 2010).

Parenteral injections

Common intramuscular injection sites are the thigh and mantle (orbicularis muscle) (Banks 2010).

The flanks are preferred for subcutaneous (SC) injections, however these furred areas are less accessible in a balled hedgehog. The dermis beneath the spiny skin is poorly vascularized, therefore absorption of fluids or medications injected SC under spiny skin may be poorly absorbed (Banks 2010). SC injections beneath the mantel, should not be placed too laterally or ventrally; if the animal begins to roll up, the injection can inadvertently enter the thoracic cavity or peritoneal cavity. Injections in the shoulders or neck should also be avoided. as large fat depotscan impair the absorption (Johnson-Delaney 2006; Fehr and Sassenburg 2015, Ivey & Carpenter 2012).

Fluid therapy

Administer fluids intravenously via the cephalic vein or through intraosseous catheters placed in the proximal or distal tibia or the proximal femur (Heatley 2008, Banks 2010).

Important medical conditions

  • Corneal ulceration (Ivey & Carpenter 2012)
  • Dental disease, including periodontal disease (D’Agostino, Ivey & Carpenter 2012)
  • Dermatophytosis (Ivey & Carpenter 2012)
  • Dilated cardiomyopathy, commonly affects males over 1 year of age (Ivey & Carpenter 2012, D’Agostino)
  • Leg and foot injury (wire cages and running wheels) Lightfoot 1998
  • Mange
  • Neoplasia, including oral neoplasia, skin neoplasia, and uterine tumors (Ivey & Carpenter 2012, Heatley 2005)
  • Obesity, hepatic lipidosis (D’Agostino, Ivey & Carpenter)
  • Ocular proptosis (Ivey & Carpenter 2012, Wheler 2001)
  • Wobbly hedgehog syndromeWobbly hedgehog syndrome is a progressive, demyelinating paralysis condition first described in the 1990s in captive African hedgehogs (Garner and Graesser 2006, Banks 2010, Graesser 2006, Ivey & Carpenter 2012). The incidence of disease is approximately 10% in North America (Ivey & Carpenter 2012, Graesser 2006). Onset typically occurs between 1-36 months of age. Clinical signs include falling to one side, hunched posture, seizure activity, tremors, exophthalmos, muscle atrophy, dysphagia, and paresis which leads to ascending paralysis. One of the earliest signs is an inability to roll up (Ivey & carpenter 2012).Intervertebral disc disease has been reported in hedgehogs and is an important differential diagnosis for neurologic signs (D’Agostino).


Zoonotic potential


Hedgehogs are often asymptomatic carriers of several strains of Salmonella, particularly
Salmonella tilene, S. typhimurium, and S. enteritiditis (Ivey & Carpenter 2012).

Hedgehogs carry a variety of dermatophytes and therefore protection with gloves while handling is recommended (Riley and Chomel 2005).

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References